I have a big maven project which has smaller child modules. I imported the project using m2e eclipse plugin and i got lots of compilation errors in eclipse.
After i built the whole project using mvn clean install some of the errors are gone(because maven plugin is able to find those dependencies in local repository and reference them from there), but the child modules still show lots of compilation error because the child modules' dependencies are missing from local repo. The dependencies are getting copied in a /lib folder inside target folder of child module.
Related
A multi-module maven project will be buit successfully from the command line using mvn clean install and is loaded successfully in vscode without any compilation errors.
When the same project is opened in Eclipse (version Version: 2022-09 (4.25.0), Build id: 20220908-1902), I see compilation errors for dependencies not resolved for example:
The import com.ibm cannot be resolved
I tried everything to resolve this error, nothing worked, for example:
Update maven project
Project / Clean
Remove maven feature, delete the project, reimport, and convert back to maven
The strange thing is that if I delete the repository folder from <user-home>\m2.\repository and make a simple change to any pom.xml file, the entire repository folder is downloaded. Also, I located the JAR file using VSCode (ctrl-click) and I can see the related JAR logEnglish-1.0.jar in the local .m2 repository folder <user-home>\.m2\repository\logEnglish\logEnglish\1.0\logEnglish-1.0.jar.
The problem is that only Eclipse is reporting compilation errors and a lot or maybe all of the maven dependencies are not resolved. This is also affecting the debugging option and it breaks due to such compilation errors.
Another thing I noticed is that the Maven Dependencies folder is not showing on the Project Explorer no in Package Explorer, but I can see Maven Dependencies entry in Project Properties -> Configure Build Path -> Libraries.
Please help resolve this issue so that I can clear the compilation errors in Eclipse.
Update 1:
I created a simple parent/child pom with one inner module. I was able to reproduce the problem right away.
See attached snapshots for details.
The compile errors will show only when you open the parent project. If you open the inner module directly as a separate project, no compile errors will show and I can run and debug the project. However, if I try to debug the parent project, I will get a warning due to compile errors, and I can run the project only and only after I added the jar of the inner module to the classpath of the debug configuration. If I don't add the jar file, I will get this error Error: Could not find or load main class training.FirstProjectClass. The project is being built successfully using mvn clean install and that's why I can run the project. If I run mvn clean then I cannot run the parent project.
Also, notice how the maven dependencies folder will show if you open the inner project directly, but, it won't show if you open the parent project.
In addition, I noticed if I add the inner project to the classpath of the debug config then it works also without building the project and without generating the jar file using mvn clean install.
Based on the above, the problem boils down to:
How we can resolve the dependencies of the inner modules when you open the project using the parent maven project?
If we can resolve the errors, then we can run without seeing the warning, and we have the assurance that the project is clear before running the mvn clean install command.
Is there a command that will let Maven use the Referenced Libraries when building a project?
See the Dependencies section of Maven / POM Reference:
The cornerstone of the POM is its dependency list. Most every project depends upon others to build and run correctly, and if all Maven does for you is manage this list for you, you have gained a lot. Maven downloads and links the dependencies for you on compilation and other goals that require them. As an added bonus, Maven brings in the dependencies of those dependencies (transitive dependencies), allowing your list to focus solely on the dependencies your project requires.
I have a plug-in project with several dependencies. Among them, there are a couple that are NOT in the official p2 Eclipse repository. They have been installed manually from its "private" update site.
Tycho can not compile the plug-in since it cannot find out where the local dependency is.
[ERROR] Missing requirement: es.uma.lcc.e-motions 2.0.1.qualifier requires 'bundle es.upv.dsic.issi.moment.mdt.maudedaemon 1.3.6' but it could not be found
These dependencies are jars in the eclipse/plugins folder. Can I add this folder as repository to my generated pom.xml?
I am trying to import nutch 1.4 into Eclipse. I cloned git repository and then build it using Maven. Then, I imported it in Eclipse as Maven project, but I'm getting the following error:
The archive: /home/devang/.m2/repository/javax/jms/jms/1.1/jms-1.1.jar which is referenced by the classpath, does not exist.
I've seen this behaviour when I had a project already imported in Eclipse, but then deleted the local Maven repository.
To solve this, make m2eclipse re-download the project's dependencies:
Right-click on the project and select Maven > Update Project...
Select Force Update of Snapshots/Releases and hit OK
Eclipse Indigo; m2e 1.1.0; Maven integration for WTP 0.15.3; Maven 3.0.4
My web project has some dependency projects in the same workspace. All projects are installed. When i run maven install, except to see all dependencies in WEB-INF/lib.
When i run maven install plugin or maven war plugin, the WEB-INF/lib will be filled with dependencies, but they are a lot more than i expected, from the "dependency Hierarchy" or "Effective POM" view of the POM file, or from Maven dependencies in classpath view, i can not find the dependencies.
Run Maven->update projects does not help.
So where these dependencies come from or where should i start to debug?
EDIT
Previously my project has a large dependency tree(100+ jars), some of them are not needed, so i decided to remove them. My project depends on a common project, which has some not needed dependencies, i remove them from POM dependencies and run maven install for the whole projects dependency tree, success. then i run maven install on my project, it should not include the jars i removed from the common project, but, unfortunately they are there in WEB-INF/lib.
If you want to know where your dependencies are coming from, run:
mvn dependency:tree
from the command line. This shows how transitive dependencies are pulled in from your declared dependencies.
You can also run:
mvn dependency:analyze
to see if you can remove any unused dependencies to lessen the number of JARs packaged.
Problem solved, I delete the whole project and import from remote, run maven-install, it worked. Still have no idea why it not work before even after i run "maven clean install" on all dependency projects.